Intro to Acute Renal Failure and Clearance Flashcards
FENa is_____ when AKI is caused by prerenal azotemia.
less than 1%
What will the UA findings be in Glomerulonephritis?
- Variable tonicity
- heme pigment
- ***sediment exam reveals RBC and RBC casts***
Normal plasma K+?
4.5 ± 0.6 mEq/L
The most commom intrarenal injury is acute tubular necrosis (ATN) caused by either _____ or _____.
- ischemia
- nephrotoxins (drugs)
Normal plasma BUN?
12 ± 4 mg/dL
Normal anion gap?
9 ± 2 mEq/L
What does ATN stand for?
acute tubular necrosis
Normal plasma Cl-?
104 ± 3 mEq/L
Normal plasma fasting glucose?
90 ± 30 mg/dL
Normal plasma Cr?
1.0 ± 0.3 mg/dL
Name 2 examples of vascular diseases that cause intrinsic renal disease.
- cholesterol emboli
- renal vein thrombosis
Name 2 examples of glomerular diseases that cause intrinsic renal disease.
- acute glomerulonephritis
- hemolytic uremic syndrome
AKI results in reduced clearance of nitrogenous waste products to produce a state called ______.
azotemia
Prompt restoration of intravascular volume restores RBF and GFR and prevents ____ in AKI.
structural ischemic renal injury
Interpret these UA findings:
- Isotonic urine
- +/- heme pigment
- white blood cell casts
- ***eosinophils (with allergic interstitial nephritis)
AIN
Intravascular volume depletion is suggested by what PE findings?
- decrease in weight
- flat neck veins (NO JVD)
- postural changes in blood pressure and/or pulse
- edema
- pulmonary rales
- S3 gallop
What are the 2 general categories of pre-renal azotemia causes?
- decreased ECF volume
- increased ECF volume
Normal blood gas pH?
7.42 ± 0.02
Name 2 serious complications of ATN and why they occur.
- Infections (due to decreased leukocyte function)
- GI hemorrhage (due to increased acid secretion ie stress, ulcers)
Normal plasma cholesterol?
140-200 mg/dL
Normal plasma Osmolality?
285 ± 3 mosm/kg H2O
What will the urinary Na concentration be in post-renal azotemia?
high (greater than 40)
______ casts are composed primarily of a mucoprotein, Tamm-Horsfall protein, secreted by tubule cells.
Hyaline
Hyaline casts are composed primarily of a ______ called Tamm-Horsfall protein, which is secreted by tubule cells.
mucoprotein
Interpret these UA findings:
- Tonicity usually isotonic or hypotonic
- usually heme is negative unless superimposed infection
- Micro may be totally benign or show evidence of superimposed infection (e.g. RBCs & WBCs)
an obstructive pathology
______ is the most common cause of an abrupt fall in GFR in a hospitalized patient.
Prerenal azotemia
What will the urinary Cr concentration be in post-renal azotemia?
low (Ucr/Pcr ratio less than 10)
Interpret these UA findings:
- Relatively high specific gravity,
- no heme pigment
- normal sediment (i.e. any casts are waxy or finely granular)
prerenal azotemia
Give 4 causes of decreases ECF volume that can result in pre-renal AKI.
- Renal losses
- Third space losses
- GI losses
- Hemorrhage
Typically, the FENa is______ in urinary obstruction.
greater than 2%
______ refers to the constellation of signs and symptoms of multiple organ dysfunction caused by retention of “uremic toxins” and lack of renal hormones due to acute or chronic kidney injury.
Uremia
What are the 3 broad types of disorders that can cause AKI?
- pre-renal
- intrinsic
- post-renal
Normal plasma PO4-?
4.0 ± 1.0 mg/dL
What will the UA findings be in Prerenal azotemia?
- Relatively high specific gravity
- no heme pigment
- normal sediment (i.e. any casts are waxy or finely granular)
Interpret these UA findings:
- Typically isotonic
- variable heme pigment (+ if from hemolysis or rhabdomyolysis)
- ***Sediment exam will show pigmented coarsely granular casts and renal tubular epithelial cells (RTEs)
ATN
Name some s/s of uremia.
- nausea/vomiting
- abdominal pain
- diarrhea
- weakness/fatigue
What will the UA findings be in ATN?
- Typically isotonic
- variable heme pigment (+ if from hemolysis or rhabdomyolysis)
- ***Sediment exam will show pigmented coarsely granular casts and renal tubular epithelial cells (RTEs)
Urinary casts are typically formed in the _____ or the ______.
- distal convoluted tubule (DCT)
- collecting duct (distal nephron)
The most common intrarenal injury is _____ caused by either ischemia or nephrotoxins (drugs).
acute tubular necrosis (ATN)
FENa is less than 1% when AKI is caused by _____.
prerenal azotemia
Normal plasma Na?
140 ± 3 mEq/L
What is the most sensitive test for post-renal obtructions?
renal ultrasound
Hyaline casts are composed primarily of a mucoprotein, called _____, which is secreted by tubule cells.
Tamm-Horsfall protein
Intrinsic renal disease is divided into four types based on the four structures found in the kidney: ____, ____, ____, and ____.
- vessels
- glomeruli
- interstitium
- tubules
______ restores RBF and GFR and prevents structural ischemic renal injury in AKI.
Prompt restoration of intravascular volume
Interpret these UA findings:
- Variable tonicity
- heme pigment
- ***sediment exam reveals RBC and RBC casts
glomerulonephritis
______ is defined as a rapid reduction in glomerular filtration rate manifested by a rise in plasma creatinine (Pcr) concentration, urea and other nitrogenous waste products.
Acute kidney injury (AKI)
Prolonged pre-renal azotemia may result in ______.
acute tubular necrosis (ATN)
The renal tubules secrete mucoproteins and when these proteins “gel” in the tubules, they form _____.
casts
What will the urine Na concentration in pre-renal azotemia?
low (less than 20)
The FENa is greater than 2% when AKI is caused by _____.
something other than a pre-renal azotemia
What will the UA findings be in AIN?
- Isotonic urine
- +/- heme pigment
- white blood cell casts
- ***eosinophils (with allergic interstitial nephritis)
Acute kidney injury (AKI) is defined as?
a rapid reduction in glomerular filtration rate manifested by a rise in plasma creatinine (Pcr) concentration, urea, and other nitrogenous waste products
Name an example of tubular disease that causes intrinsic renal disease.
Ischemic/nephrotoxic acute tubular necrosis (ATN)
Give 4 causes of systemic arterial vasodilation that can result in pre-renal AKI.
- Cirrhosis
- Sepsis
- Medication
- Autonomic Neuropathy
Normal plasma Ca++?
9.5 ± 1.0 mg/dL
The FENa is ______ when AKI is NOT caused by a pre-renal azotemia.
greater than 2%
Name 3 examples of interstitial diseases that cause intrinsic renal disease.
- Acute interstitial nephritis (e.g. allergic interstitial nephritis (AIN)
- infection
- myeloma kidney
What is the equation for calculating FENa?
FENa = (UNa/PNa) ÷ (UCr/Pcr ) X 100 (expressed in %)
Normal plasma CO2?
27 ± 2 mEq/L *** note this is venous. arterial = 24
Normal specific gravity?
1.010
AKI results in reduced clearance of ______ to produce a state called azotemia.
nitrogenous waste products
Give 4 causes of decreased cardiac output that can result in pre-renal AKI.
- CHF
- Myocardial Infarction
- Valvular disease
- Pericardial tamponade
What will the urine Cr concentration in pre-renal azotemia?
high (Ucr/Pcr ratio greater than 20)
What will the UA findings be in obstructive pathologies?
- Tonicity usually isotonic or hypotonic
- usually heme is negative unless superimposed infection
- Micro may be totally benign or show evidence of superimposed infection (e.g. RBCs & WBCs)